WO2002101267A1 - Flat packing and method for the production thereof - Google Patents

Flat packing and method for the production thereof Download PDF

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Publication number
WO2002101267A1
WO2002101267A1 PCT/EP2002/002018 EP0202018W WO02101267A1 WO 2002101267 A1 WO2002101267 A1 WO 2002101267A1 EP 0202018 W EP0202018 W EP 0202018W WO 02101267 A1 WO02101267 A1 WO 02101267A1
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WO
WIPO (PCT)
Prior art keywords
nonwoven
impregnated
flat gasket
fibers
ptfe
Prior art date
Application number
PCT/EP2002/002018
Other languages
German (de)
French (fr)
Inventor
Steffen Kosack
Thomas Klenk
Ulrich Liedtke
Frank Schultz
Original Assignee
Carl Freudenberg Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Carl Freudenberg Kg filed Critical Carl Freudenberg Kg
Priority to EP02778871A priority Critical patent/EP1395767B1/en
Priority to CA002450697A priority patent/CA2450697A1/en
Priority to DE50209832T priority patent/DE50209832D1/en
Priority to MXPA03011543A priority patent/MXPA03011543A/en
Priority to US10/480,204 priority patent/US7309520B2/en
Publication of WO2002101267A1 publication Critical patent/WO2002101267A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/06—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces
    • F16J15/10—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with non-metallic packing
    • F16J15/102—Sealings between relatively-stationary surfaces with solid packing compressed between sealing surfaces with non-metallic packing characterised by material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
    • B29B15/08—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of reinforcements or fillers
    • B29B15/10—Coating or impregnating independently of the moulding or shaping step
    • B29B15/12—Coating or impregnating independently of the moulding or shaping step of reinforcements of indefinite length
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
    • Y10T442/2311—Coating or impregnation is a lubricant or a surface friction reducing agent other than specified as improving the "hand" of the fabric or increasing the softness thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
    • Y10T442/2861—Coated or impregnated synthetic organic fiber fabric

Definitions

  • the invention relates to a flat gasket made of a nonwoven fabric impregnated with an active ingredient, in particular polytetrafluoroethylene (PTFE), as a sealing element, and a method for producing such a flat gasket.
  • PTFE polytetrafluoroethylene
  • Filler materials mineral additives and graphite, coal, metal and metal inlays or equivalent are usually used as fillers
  • the fiber materials can also be provided with special impregnations.
  • PTFE In combination with good sealing and mechanical material properties at high temperatures, PTFE has established itself as a material.
  • the invention has for its object to provide a flat gasket that has a high sealing behavior in conjunction with a particularly good mechanical material and temperature behavior with the best chemical resistance.
  • the starting point for the production are mechanically bound nonwovens with a tangled or random fiber structure.
  • the predominant mechanical bond of the fleece is of particular importance here, since a chemical bond can evaporate during later use at high temperatures and thus leads to insufficient cohesion or For example, when used later as a seal in piping systems in the chemical industry leads to insufficient chemical resistance.
  • the good mechanical support effect, as well as openness and porosity, is based on the fiber length, which can range from 3 to 20 mm.
  • the basis weight of the nonwovens is approx. 20 to 500 g / m 2 .
  • the short fiber length leads to strong porosity, which is an advantage for later impregnation.
  • nonwovens made from other fibers and fiber mixtures, e.g. made of polyimide (Pl), polybenzinidazole (PBI), polyester (PES), glass fibers (GF), aramid fibers (AF) or basalt fibers can be used depending on the application.
  • the nonwoven is bound mechanically e.g. by hydroentangling or needles. Mechanical strengthening is important because, in contrast to a chemical bond, it has high stability even at high temperatures.
  • the great advantage of the impregnation of nonwovens compared to, for example, the also known impregnation of fabrics is that in nonwovens, compared to fabrics in which the fibers are bundled, the fibers are isolated and well distributed, and so each fiber is coated with impregnation, whereas in the case of fabrics or braid webs, the impregnation is only on the outside, which leads to significantly poorer tightness, particularly gas tightness.
  • the invention also relates to a method for producing a flat gasket according to claim 9. Further advantageous refinements of the method according to the invention are described in claims 10 to 15.
  • the length of time in the impregnation bath depends on the desired degree of impregnation and the active ingredient used.
  • the impregnation used is predominantly pure aqueous PTFE dispersion or mixtures of aqueous PTFE dispersion with mineral fillers which contain, for example, up to 50% by weight of graphite, talc, mica or molybdenum disulfide based on the dry weight of PTFE as an inorganic filler and conventional dispersing agents.
  • the impregnation bath can be circulated depending on the impregnation mixture used, e.g. with a stirrer or by pumping to always ensure an even mix in the impregnation bath. This ensures that the corresponding nonwoven web can be soaked to the maximum degree of saturation (up to approximately 95-98% active ingredient).
  • impregnation is again pressed out of the fleece in a downstream stripping section between two rollers. This is also to achieve a particularly good distribution of the active ingredient in the nonwoven web.
  • the roll gap is between approx. 50% of the original fleece thickness and maximum embossing thickness.
  • the impregnated nonwoven web is preferably dried in a continuous oven at a temperature of about 30 to 300 ° C.
  • the impregnated fleece is now only a solid, homogeneous fiber composite that consists exclusively of the high-quality fibers of the fleece and the combination of PTFE and active ingredients, and is therefore chemically and mechanically very stable even without the sintering process
  • Flat gasket represents, which due to the low compression is particularly suitable for applications such as for adaptation to sealing points with high surface roughness or e.g. in the case of enamelled flanges or glass flanges etc., a strong deformation of the seal, i.e. an extremely flexible seal is required.
  • the heat input into the PTFE nonwoven sealing membrane is increased when passing through the rollers, for example due to a slower web speed and at the same time increased pressure on the PTFE nonwoven membrane through the rollers, it is also possible to sinter the PTFE nonwoven membrane almost continuously.
  • a correspondingly high pressure it is also possible in this way to laminate several (preferably 2 to 10) of these PTFE nonwoven webs together to form a nonwoven composite. For example, to laminate differently compressed or thick PTFE nonwoven webs or PTFE nonwoven webs that were manufactured with different PTFE impregnations.
  • Fig. 1 shows a device for producing flat seals
  • the laminating system is composed here in detail of the PTFE-impregnated nonwoven webs 1 wound on spreader rolls 2 with associated tensioning and braking devices. This is followed by a preheating section 3, in which a large amount of heat is introduced into the PTFE nonwoven web by heating the warm air chamber to 30-400 ° C.
  • the PTFE nonwoven web 1 to be compressed and smoothed or the PTFE nonwoven webs 1 to be connected and compressed is conveyed through the calender section continuously by three rotating calender rolls 4 arranged one above the other and by triple deflection between the calender rolls.
  • the web speed of the PTFE nonwoven web 1 is, depending on the desired residence time, preferably between 0.1 to 2 m / min.
  • the rollers 4 are heated to temperatures between 30 to 300 ° C.
  • the gap between the metal rollers can be chosen virtually arbitrarily due to the independent horizontal displacement of the rollers.
  • the gap between the rollers is preferably between 95% and 50% of the thickness of the undensified PTFE nonwoven web 1 or between 95% and 50% of the total thickness of several PTFE nonwoven webs 1, which is the sum of the individual PTFE to be joined together - Nonwoven webs 1 composed.
  • the PTFE nonwoven web which has been compressed and heated up to such an extent, is then strongly cooled and then cooled on a cooling section and then rolled up on a winding frame 5.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Gasket Seals (AREA)
  • Sealing Material Composition (AREA)

Abstract

The invention relates to a flat packing consisting of at least one nonwoven material layer, which is comprised of a textile construction made of asbestos-free fibers or of fiber blends and which is impregnated with a polymer. The sealing element (1) is at least comprised of a nonwoven material that is impregnated with polytetrafluoroethylene.

Description

Flachdichtung und Verfahren zu ihrer Herstellung Flat gasket and process for its manufacture
Beschreibungdescription
Die Erfindung befasst sich mit einer Flachdichtung aus einem mit einem Wirkstoff, insbesondere Polytetrafluorethylen (PTFE), getränkten Vliesstoff als Dichtelement sowie einem Verfahren zur Herstellung einer solchen Flachdichtung.The invention relates to a flat gasket made of a nonwoven fabric impregnated with an active ingredient, in particular polytetrafluoroethylene (PTFE), as a sealing element, and a method for producing such a flat gasket.
Für Flanschverbindungen für den Einsatz in der (petro-)chemischen Industrien beziehungsweise für energie- und verfahrenstechnische Anlagen werden häufig Flachdichtungen aus gummigebundenen Werkstoffen sowie aus gepreßten Platten aus gepreßter Folie flexiblen Graphits verwendet.For flange connections for use in the (petro-) chemical industries or for energy and process engineering systems, flat seals made of rubber-bonded materials and made of pressed sheets made of flexible graphite are often used.
Als Füllstoffe werden dann meist Faserwerkstoffe, mineralische Zusatzstoffe zusätzlich Graphit, Kohle, Metall- und Metalleinlagen oder entsprechendeFiller materials, mineral additives and graphite, coal, metal and metal inlays or equivalent are usually used as fillers
Kombinationen daraus verwendet. Die Faserwerkstoffe können auch mit speziellen Imprägnierungen versehen sein.Combinations of them used. The fiber materials can also be provided with special impregnations.
Bei Flachdichtungen, bei denen eine äußerst hohe chemische Beständigkeit inFor flat gaskets, where an extremely high chemical resistance in
Kombination mit guten Abdicht- und mechanischen Werkstoffeigenschaften bei hohen Temperaturen gefordert wird, hat sich PTFE als Werkstoff etabliert.In combination with good sealing and mechanical material properties at high temperatures, PTFE has established itself as a material.
Durch die DE-A 44 19 007 ist es bekannt, Flachdichtungen aus mindestens einem Vliesstoff-Prepreg zu bilden, bei dem ein Flächengebilde aus asbestfreien Fasern oder Fasergemischen mit vorvernetzbaren Lösungen, Dispersionen oder Suspensionen einer reaktiven Polymermischung getränkt, durch Trocknung bei erhöhter Temperatur vorvernetzt und gegebenenfalls mit Kunststoff- oder Metallfolien zusammenlaminiert werden.From DE-A 44 19 007 it is known to form flat seals from at least one nonwoven prepreg, in which a flat structure is made of asbestos-free fibers or fiber mixtures impregnated with pre-crosslinkable solutions, dispersions or suspensions of a reactive polymer mixture, pre-crosslinked by drying at elevated temperature and, if necessary, laminated together with plastic or metal foils.
Aus dem Dokument EP-B 654 625 sind Flachdichtungen bekannt, die aus mikroporösen, verstreckten PTFE bestehen und wenigstens teilweise mit einem lösungsmittelresistenten Kunststofflack versehen sind.From the document EP-B 654 625 flat seals are known which consist of microporous, stretched PTFE and are at least partially provided with a solvent-resistant plastic lacquer.
Dokument US-A 5,997,008 beschreibt einen Dichtring, der aus einem gewellten Metallring besteht und der mindestens auf einer Seite eine nichtmetallische Beschichtung mit einem geringen Reibungskoeffizienten beispielsweise aus PTFE als Mikrodichtungsschicht aufweist.Document US-A 5,997,008 describes a sealing ring which consists of a corrugated metal ring and which has at least on one side a non-metallic coating with a low coefficient of friction, for example made of PTFE as a micro-sealing layer.
Der Erfindung liegt die Aufgabe zugrunde, eine Flachdichtung zu schaffen, die ein hohes Abdichtverhalten in Verbindung mit einem besonders guten mechanischen Werkstoff- und Temperaturverhalten bei bester chemischer Beständigkeit aufweist.The invention has for its object to provide a flat gasket that has a high sealing behavior in conjunction with a particularly good mechanical material and temperature behavior with the best chemical resistance.
Erfindungsgemäß wird die Aufgabe durch eine gattungsgemäß angegebene Flachdichtung mit den in Anspruch 1 angegebenen Merkmalen gelöst.According to the invention the object is achieved by a generic flat gasket with the features specified in claim 1.
Weitere vorteilhafte Ausgestaltungen der Erfindung sind in den Ansprüchen 2 bis 8 dargelegt.Further advantageous embodiments of the invention are set out in claims 2 to 8.
Ausgangspunkt für die Herstellung sind dabei mechanisch gebundene Vliesstoffe mit wirrer bzw. randomartiger Faserstruktur. Dabei ist insbesondere die überwiegende mechanische Bindung des Vlieses von Bedeutung, da eine chemische Bindung sich beim späteren Einsatz bei hohen Temperaturen verflüchtigen kann und damit zu ungenügendem Zusammenhalt führt oder beispielsweise beim späteren Einsatz als Abdichtung in Rohrleitungssystemen der chemischen Industrie zu ungenügender chemischer Beständigkeit führt. Die gute mechanische Stützwirkung, sowie Offenheit und Porosität basiert hierbei auf der Faserlänge, die in einem Längenbereich zwischen 3 bis 20 mm liegen können. Das Flächengewicht der Vliese beträgt hierbei rd. 20 bis 500 g/m2. Die kurze Faserlänge führt hierbei zu einer starken Porosität, was für die spätere Imprägnierung von Vorteil ist.The starting point for the production are mechanically bound nonwovens with a tangled or random fiber structure. The predominant mechanical bond of the fleece is of particular importance here, since a chemical bond can evaporate during later use at high temperatures and thus leads to insufficient cohesion or For example, when used later as a seal in piping systems in the chemical industry leads to insufficient chemical resistance. The good mechanical support effect, as well as openness and porosity, is based on the fiber length, which can range from 3 to 20 mm. The basis weight of the nonwovens is approx. 20 to 500 g / m 2 . The short fiber length leads to strong porosity, which is an advantage for later impregnation.
Aufgrund der guten Temperatur- und chemischen Beständigkeit und der hervorragenden mechanischen Festigkeit werden vorwiegend mechanisch gebundene Aramidvliese verwendet, wobei aber auch Vliese aus anderen Fasern und Fasermischungen z.B. aus Polyimid (Pl), Polybenzinidazol (PBI), Polyester (PES), Glasfasern (GF), Aramidfasern (AF) oder Basaltfasern je nach Anwendung eingesetzt werden können. Die Bindung des Vliesstoffes erfolgt mechanisch z.B. durch Wasserstrahlverfestigung oder Nadeln. Die mechanische Verfestigung ist insofern von Bedeutung, da sie im Gegensatz zu einer chemischen Bindung eine hohe Stabilität auch bei hohen Temperaturen hat. Die Vliesstoffbahn selbst hat eine Dicke <= 5 mm, vorzugsweise von 1 bis 2,5 mm.Due to the good temperature and chemical resistance and the excellent mechanical strength, mainly mechanically bonded aramid nonwovens are used, but nonwovens made from other fibers and fiber mixtures, e.g. made of polyimide (Pl), polybenzinidazole (PBI), polyester (PES), glass fibers (GF), aramid fibers (AF) or basalt fibers can be used depending on the application. The nonwoven is bound mechanically e.g. by hydroentangling or needles. Mechanical strengthening is important because, in contrast to a chemical bond, it has high stability even at high temperatures. The nonwoven web itself has a thickness <= 5 mm, preferably from 1 to 2.5 mm.
Der große Vorteil der Imprägnierung von Vliesen gegenüber z.B. dem auch bekannten Imprägnieren von Geweben besteht darin, daß in Vliesen, im Vergleich zu Geweben bei denen die Fasern gebündelt sind, die Fasern vereinzelt und gut verteilt vorliegen und so jede Faser mit Imprägnierung umhüllt wird, wohingegen bei Geweben oder Geflechtbahnen die Imprägnierung nur außen aufliegt was zu einer wesentlich schlechteren Dichtheit besonders Gasdichtheit führt. Die Erfindung betrifft auch ein Verfahren zur Herstellung einer Flachdichtung gemäß Anspruch 9. Weitere vorteilhafte Ausgestaltungen des erfindungsgemäßen Verfahrens sind in den Ansprüchen 10 bis 15 beschrieben.The great advantage of the impregnation of nonwovens compared to, for example, the also known impregnation of fabrics is that in nonwovens, compared to fabrics in which the fibers are bundled, the fibers are isolated and well distributed, and so each fiber is coated with impregnation, whereas in the case of fabrics or braid webs, the impregnation is only on the outside, which leads to significantly poorer tightness, particularly gas tightness. The invention also relates to a method for producing a flat gasket according to claim 9. Further advantageous refinements of the method according to the invention are described in claims 10 to 15.
Die quasi-kontinuerliche Imprägnierung des Vliesstoffes mit beispielsweise einer 50 bis 60 Gew.% PTFE, 3 bis 5 Gew.% Alkylphenolethoxylat, < 0,2 Gew.% Ammoniumpentadecafluoroctanoat und Rest demineralisiertes Wasser enthaltenden PTFE-Dispersion erfolgt, in dem die Vliesbahnen automatisch durch ein Imprägnierbad mit einer Geschwindigkeit von rd. 0,1 - 5 m/min gezogen werden. Die Verweildauer im Imprägnierbad ist abhängig vom gewünschten Imprägniergrad und dem eingesetzten Wirkstoff. Als Imprägnierung werden vorwiegend reine wäßrige PTFE-Dispersion oder Gemische aus wässriger PTFE-Dispersion mit mineralischen Füllstoffen eingesetzt, die beispielsweise bis zu 50 Gew.% Graphit, Talkum, Glimmer oder Molybdandisulfid bezogen auf die Trockenmasse an PTFE als anorganischen Füllstoff und übliche Dispergierhilfsmittel enthalten. Dabei kann das Imprägnierbad je nach verwendeter Imprägniermischung umgewälzt werden, z.B. mit einem Rührer oder durch Pumpen, um immer eine gleichmäßige Mischung im Imprägnierbad sicherzustellen. Dadurch ist sichergestellt, daß die entsprechende Vliesbahn bis zum maximalen Sättigungsgrad getränkt werden kann (bis ungefähr 95-98% Wirkstoffanteil).The quasi-continuous impregnation of the nonwoven with, for example, a 50 to 60% by weight of PTFE, 3 to 5% by weight of alkylphenol ethoxylate, <0.2% by weight of ammonium pentadecafluorooctanoate and the remainder of demineralized water-containing PTFE dispersion, in which the nonwoven webs are carried out automatically an impregnation bath with a speed of approx. 0.1 - 5 m / min. The length of time in the impregnation bath depends on the desired degree of impregnation and the active ingredient used. The impregnation used is predominantly pure aqueous PTFE dispersion or mixtures of aqueous PTFE dispersion with mineral fillers which contain, for example, up to 50% by weight of graphite, talc, mica or molybdenum disulfide based on the dry weight of PTFE as an inorganic filler and conventional dispersing agents. The impregnation bath can be circulated depending on the impregnation mixture used, e.g. with a stirrer or by pumping to always ensure an even mix in the impregnation bath. This ensures that the corresponding nonwoven web can be soaked to the maximum degree of saturation (up to approximately 95-98% active ingredient).
In Fällen, in denen z.B. aus Gründen der Standfestigkeit gegenüber der Abdichteigenschaft ein höherer Faseranteil in der späteren Dichtung erwünscht ist, wird in einer nachgeschalteten Abstreifstrecke zwischen 2 Walzen wieder teilweise Imprägnierung aus dem Vlies herausgedrückt. Dies auch um eine besonders gute Verteilung des Wirkstoffs in der Vliesstoff bahn zu erreichen. Hierzu beträgt der Walzenspalt zwischen rd. 50 % der Ausgangsvliesdicke und maximaler Preprägdicke . Um das Austropfen der Imprägnierung zu vermeiden wird bevorzugt die Trocknung der imprägnierten Vliesstoffbahn in einem Durchlaufofen bei einer Temperatur von etwa 30 bis 300 °C durchgeführt.In cases where, for reasons of stability compared to the sealing property, a higher proportion of fibers is desired in the subsequent seal, impregnation is again pressed out of the fleece in a downstream stripping section between two rollers. This is also to achieve a particularly good distribution of the active ingredient in the nonwoven web. For this purpose, the roll gap is between approx. 50% of the original fleece thickness and maximum embossing thickness. In order to prevent the impregnation from dripping out, the impregnated nonwoven web is preferably dried in a continuous oven at a temperature of about 30 to 300 ° C.
Hierbei werden die Dispersions- sowie weitere flüchtige Imprägnierungssubstanzen so entfernt, daß das imprägnierte Vlies nun ausschließlich einen festen homogenen Faserverbund darstellt, der ausschließlich aus den hochwertigen Fasern des Vlieses und der PTFE- Wirkstoffkombination besteht und so bereits auch ohne Sintervorgang eine chemisch und mechanisch sehr stabile Flachdichtung darstellt, die aufgrund der geringen Verdichtung insbesondere für Anwendungen geeignet ist, bei der z.B. zur Anpassung an Dichtstellen mit großer Oberflächenrauhigkeit oder z.B. bei emaillierten Flanschen oder Glasflanschen usw. eine starke Verformung der Dichtung, d.h. eine noch äußerst flexible Dichtung benötigt wird.Here, the dispersion and other volatile impregnation substances are removed so that the impregnated fleece is now only a solid, homogeneous fiber composite that consists exclusively of the high-quality fibers of the fleece and the combination of PTFE and active ingredients, and is therefore chemically and mechanically very stable even without the sintering process Flat gasket represents, which due to the low compression is particularly suitable for applications such as for adaptation to sealing points with high surface roughness or e.g. in the case of enamelled flanges or glass flanges etc., a strong deformation of the seal, i.e. an extremely flexible seal is required.
Für Anwendungsfälle bei denen eine höhere Dichtheit bzw. Gasdichtheit sowie Standfestigkeit der zu verwendenden Flanschdichtungen benötigt ist, wird die PTFE-Vlies-Dichtungsbahn in einem weiteren Fertigungsschritt in einem kontinuierlichen Walz- bzw. Laminiervorgang mit Hilfe umlaufender innerlich elektrisch beheizter Stahlwalzen einer Temperatur- und Druckbehandlung unterworfen, was auf der einen Seite zu einer deutlichen Verdichtung der PTFE-Vlies-Dichtungsbahn führt und gleichzeitig aufgrund der Streichwirkung der Walzen mit einer Oberflächenrauhigkeit von Rz <= 6 μm unter gleichzeitiger Temperatureinbringung bis zu 300 °C zu einer deutlichen Oberflächenglättung und Verdichtung der Vliesbahn führt (Glätten bzw. Glattstreichen und Verkleben der PTFE-Flocken auf der Oberfläche, Ansintern) was zu einer glatten gasdichten Oberfläche führt, die so unter anderem auch eine geringere Verschmutzungsanfälligkeit der Oberfläche zur Folge hat. Wird die Wärmeeinbringung in die PTFE-Vlies-Dichtungsbahn beim Durchlaufen der Walzen erhöht, z.B. durch eine langsamere Bahngeschwindigkeit und gleichzeitig ein erhöhter Druck auf die PTFE- Vliesbahn durch die Walzen ausgeübt, so ist es auch möglich die PTFE- Vliesbahn quasi kontinuierlich durchzusintern. Durch einen entsprechend hohen Druck ist es auf diese Art und Weise auch möglich mehrere (vorzugsweise 2 bis 10) dieser PTFE-Vliesbahnen zu einem Vliesverbund zusammenzulaminieren. Dies z.B. um unterschiedlich verdichtete oder dicke PTFE-Vliesstoffbahnen bzw. PTFE-Vliesstoffbahnen die mit unterschiedlichen PTFE-Imprägnierungen hergestellt wurden, zusammenzulaminieren.For applications in which a higher level of tightness or gas tightness as well as stability of the flange seals to be used is required, the PTFE fleece sealing membrane is subjected to a further manufacturing step in a continuous rolling or laminating process with the help of rotating internally electrically heated steel rollers of a temperature and pressure treatment subject, which leads on the one hand to a clear compression of the PTFE fleece sealing membrane and at the same time due to the coating effect of the rollers with a surface roughness of Rz <= 6 μm with simultaneous temperature application up to 300 ° C to a clear surface smoothing and compression of the fleece membrane leads (smoothing or smoothing and sticking of the PTFE flakes on the surface, sintering) which leads to a smooth gas-tight surface, which among other things also results in less susceptibility to contamination of the surface. If the heat input into the PTFE nonwoven sealing membrane is increased when passing through the rollers, for example due to a slower web speed and at the same time increased pressure on the PTFE nonwoven membrane through the rollers, it is also possible to sinter the PTFE nonwoven membrane almost continuously. By means of a correspondingly high pressure, it is also possible in this way to laminate several (preferably 2 to 10) of these PTFE nonwoven webs together to form a nonwoven composite. For example, to laminate differently compressed or thick PTFE nonwoven webs or PTFE nonwoven webs that were manufactured with different PTFE impregnations.
Es zeigtIt shows
Fig. 1 eine Vorrichtung zur Herstellung von FlachdichtungenFig. 1 shows a device for producing flat seals
Die Laminieranlage setzt sich hierbei im Einzelnen aus den auf Breitstreckrollen 2 mit dazugehörigen Spann- und Bremsvorrichtungen aufgewickelten PTFE-imprägnierten Vliesbahnen 1 zusammen. Danach schließt sich eine Vorheizstrecke 3 an, bei der durch eine Beheizung der Warmluftkammer auf 30-400°C schon ein großer Wärmebetrag in die PTFE- Vliesbahn eingebracht wird.The laminating system is composed here in detail of the PTFE-impregnated nonwoven webs 1 wound on spreader rolls 2 with associated tensioning and braking devices. This is followed by a preheating section 3, in which a large amount of heat is introduced into the PTFE nonwoven web by heating the warm air chamber to 30-400 ° C.
Danach wird die zu verdichtende und zu glättende PTFE-Vliesbahn 1 oder die zu verbindenden und zu verdichtenden PTFE-Vliesbahnen 1 durch drei übereinanderangeordneten sich drehende Kalanderwalzen 4 kontinuierlich und über dreifaches Umlenken zwischen den Kalanderwalzen durch die Kalanderstrecke durchgefördert. Dabei beträgt die Bahngeschwindigkeit der PTFE-Vliesbahn 1 je nach gewünschter Verweildauer hierbei vorzugsweise zwischen 0,1 bis 2 m/min. Die Walzen 4 werden hierbei auf Temperaturen zwischen 30 bis 300 °C beheizt.Thereafter, the PTFE nonwoven web 1 to be compressed and smoothed or the PTFE nonwoven webs 1 to be connected and compressed is conveyed through the calender section continuously by three rotating calender rolls 4 arranged one above the other and by triple deflection between the calender rolls. The web speed of the PTFE nonwoven web 1 is, depending on the desired residence time, preferably between 0.1 to 2 m / min. The rollers 4 are heated to temperatures between 30 to 300 ° C.
Zur Verdichtung der PTFE-Vliesbahn 1 , d.h. zur Druckeinbringung, kann der Spalt zwischen den Metallwalzen durch die voneinander unabhängige horizontale Verschiebbarkeit der Walzen quasi beliebig gewählt werden. Vorzugsweise beträgt der Spalt zwischen den Walzen zwischen 95% und 50 % der Dicke der unverdichteten PTFE-Vliesbahn 1 bzw. zwischen 95% und 50 % der Gesamtdicke von mehrerer PTFE-Vliesbahnen 1 , die sich aus der Summe der Einzelnen der miteinander zu verbindenden PTFE-Vliesbahnen 1 zusammensetzt.For the compression of the PTFE nonwoven web 1, i.e. to apply pressure, the gap between the metal rollers can be chosen virtually arbitrarily due to the independent horizontal displacement of the rollers. The gap between the rollers is preferably between 95% and 50% of the thickness of the undensified PTFE nonwoven web 1 or between 95% and 50% of the total thickness of several PTFE nonwoven webs 1, which is the sum of the individual PTFE to be joined together - Nonwoven webs 1 composed.
Die so stark verdichtete und aufgeheizte eventuell zusammenlaminierte PTFE- Vliesbahn wird dann auf einer Kühlstrecke abgekühlt und anschließend auf einem Wickelbock 5 aufgerollt. The PTFE nonwoven web, which has been compressed and heated up to such an extent, is then strongly cooled and then cooled on a cooling section and then rolled up on a winding frame 5.

Claims

Patentansprüche claims
1. Flachdichtung aus mindestens einer Vliesstoffschicht, die aus einem Flächengebilde aus asbestfreien Fasern oder Fasergemischen besteht und mit einem Polymer imprägniert ist, dadurch gekennzeichnet, dass das Dichtelement (1 ) wenigstens aus einem mit Polytetrafluorethylen imprägnierten Vliesstoff besteht.1. Flat gasket made of at least one non-woven material layer, which consists of a flat structure of asbestos-free fibers or fiber mixtures and is impregnated with a polymer, characterized in that the sealing element (1) consists of at least one non-woven material impregnated with polytetrafluoroethylene.
2. Flachdichtung nach Anspruch 1 , dadurch gekennzeichnet, dass der Vliesstoff mit einer wässrigen PTFE-Dispersion imprägniert ist.2. Flat gasket according to claim 1, characterized in that the nonwoven fabric is impregnated with an aqueous PTFE dispersion.
3. Flachdichtung nach Anspruch 2, dadurch gekennzeichnet, dass die PTFE-Dispersion anorganische Füllstoffe enthält.3. Flat gasket according to claim 2, characterized in that the PTFE dispersion contains inorganic fillers.
4. Flachdichtung nach Anspruch 2 oder 3, dadurch gekennzeichnet, dass die PTFE-Dispersion bis zu 50 Gew.% Graphit, Talkum, Glimmer oder Molybdandisulfid bezogen auf die Trockenmasse an PTFE als anorganischen Füllstoff enthält.4. Flat gasket according to claim 2 or 3, characterized in that the PTFE dispersion contains up to 50% by weight of graphite, talc, mica or molybdenum disulfide based on the dry mass of PTFE as an inorganic filler.
5. Flachdichtung nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass der Vliesstoff ein mechanisch gebundener Vliesstoff mit einer Faserlänge von 2 bis 100 mm, insbesondere von 3 bis 20 mm, und einem Flächengewicht von 20 bis 500 g/m2 ist.5. Flat gasket according to one of claims 1 to 4, characterized in that the nonwoven fabric is a mechanically bonded nonwoven fabric with a fiber length of 2 to 100 mm, in particular 3 to 20 mm, and a basis weight of 20 to 500 g / m 2 .
6. Flachdichtung nach Anspruch 5, dadurch gekennzeichnet, dass das die mechanische Bindung des Vliesstoffs durch Wasserstrahlverfestigung oder Nadeln durchgeführt ist.6. Flat gasket according to claim 5, characterized in that the mechanical bonding of the nonwoven is carried out by hydroentangling or needles.
7. Flachdichtung nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass der Vliesstoff aus Fasern oder Fasermischungen aus Polyimid (Pl), Polybenzinidazol (PBI), Polyester (PES), Glasfasern (GF), Aramidfasem (AF) oder Basaltfasern besteht.7. Flat gasket according to one of claims 1 to 6, characterized in that the nonwoven fabric made of fibers or fiber mixtures consists of polyimide (Pl), polybenzinidazole (PBI), polyester (PES), glass fibers (GF), aramid fibers (AF) or basalt fibers.
8. Flachdichtung nach Anspruch 7, dadurch gekennzeichnet, dass die Fasern Aramidfasem sind.8. Flat gasket according to claim 7, characterized in that the fibers are aramid fibers.
9. Verfahren zur Herstellung einer imprägnierten Flachdichtung aus mindestens einer Vliesstoffschicht, die aus einem Flächengebilde aus asbestfreien Fasern oder Fasergemischen besteht und mit einem Polymer imprägniert ist, dadurch gekennzeichnet, daß man eine mechanisch verfestigte Faservliesstoff bahn mit einer wässrigen PTFE- Dispersion imprägniert, die getränkten Faservliesstoffbahn danach durch zwei Abquetschwalzen laufen läßt, anschließend in einem Trockenofen trocknet, sodann die entstandenen Vliesstoff-Bahnen in gewünschter Anzahl unter Druck und Wärme, die ausreicht, um eine Verdichtung zu bewirken, miteinander zur fertigen Flachdichtung laminiert.9. A method for producing an impregnated flat gasket from at least one nonwoven layer, which consists of a sheet of asbestos-free fibers or fiber mixtures and is impregnated with a polymer, characterized in that a mechanically consolidated nonwoven web is impregnated with an aqueous PTFE dispersion, the impregnated The nonwoven fabric web then runs through two squeeze rolls, then dries in a drying oven, and the resulting nonwoven webs are then laminated in the desired number under pressure and heat, which is sufficient to effect compaction, to form the finished flat gasket.
10. Verfahren nach Anspruch 9, dadurch gekennzeichnet, dass die Vliesstoff bahnen vor der Verdichtung eine Dicke von kleiner 5 mm, vorzugsweise von 0,5 bis 5 mm, haben.10. The method according to claim 9, characterized in that the nonwoven webs have a thickness of less than 5 mm, preferably from 0.5 to 5 mm, before compression.
11. Verfahren nach Anspruch 9 oder 10, dadurch gekennzeichnet, dass die Trocknung der imprägnierten Vliesstoffbahn in einem Durchlaufofen bei einer Temperatur von 30 bis 300°C erfolgt.11. The method according to claim 9 or 10, characterized in that the drying of the impregnated nonwoven web takes place in a continuous oven at a temperature of 30 to 300 ° C.
12. Verfahren nach einem der Ansprüche 9 bis 11 , dadurch gekennzeichnet, dass eine Verdichtung um 5 bis 70% der Ausgangsdicke erfolgt. 12. The method according to any one of claims 9 to 11, characterized in that a compression takes place by 5 to 70% of the initial thickness.
13. Verfahren nach einem der Ansprüche 9 bis 12, dadurch gekennzeichnet, daß man das Laminieren der Vliesstoff-Bahnen aufeinander in einem beheizten Rollaminator oder in einer beheizten Doppelbandpresse durchführt und anschließend die Aushärtung in einem Trockenofen oder einer Trockenkammer vornimmt.13. The method according to any one of claims 9 to 12, characterized in that the lamination of the nonwoven webs to one another is carried out in a heated roll laminator or in a heated double belt press and then the curing is carried out in a drying oven or drying chamber.
14. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß man zwischen zwei Vliesstoff-Bahnen eine Kunststoff- oder Metallfolie laminiert.14. The method according to claim 2, characterized in that a plastic or metal foil is laminated between two nonwoven webs.
15. Verfahren nach Anspruch 3, dadurch gekennzeichnet, daß man vor dem Laminieren jeweils die Vliesstoff-Bahnen und die Kunststoff- oder Metallfolie getrennt voneinander zu ihrer bestimmungsgemäßen Endform vorkonturiert. 15. The method according to claim 3, characterized in that one pre-contoured the nonwoven webs and the plastic or metal foil separately from each other to their intended final shape before lamination.
PCT/EP2002/002018 2001-06-13 2002-02-26 Flat packing and method for the production thereof WO2002101267A1 (en)

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EP02778871A EP1395767B1 (en) 2001-06-13 2002-02-26 Flat packing and method for the production thereof
CA002450697A CA2450697A1 (en) 2001-06-13 2002-02-26 Flat packing and method for the production thereof
DE50209832T DE50209832D1 (en) 2001-06-13 2002-02-26 FLAT SEAL AND METHOD FOR THE PRODUCTION THEREOF
MXPA03011543A MXPA03011543A (en) 2001-06-13 2002-02-26 Flat packing and method for the production thereof.
US10/480,204 US7309520B2 (en) 2001-06-13 2002-02-26 Flat packing and method for the production thereof

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DE10128346A DE10128346A1 (en) 2001-06-13 2001-06-13 Flat gasket and process for its manufacture
DE10128346.6 2001-06-13

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CN102686917A (en) * 2009-11-06 2012-09-19 A.W.切斯特顿公司 Gland packing yarn

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US20070052134A1 (en) * 2005-09-08 2007-03-08 Michael Draper Planar elements incorporating basalt fibers for use in papermaking apparatus
EP1855034B1 (en) 2006-05-12 2012-12-05 Carl Freudenberg KG Gasket
EP2470366A4 (en) * 2009-08-27 2016-04-13 Whitford Corp Method for improving impact damage resistance to textile articles, and articles made therefrom
DE102012016535A1 (en) * 2012-08-14 2014-02-20 Werner Drotleff Ball-shaped hut for e.g. motorcycle, has several spherical shell sections, bottom radial sections, upper and sub-loop elements, and abutting surfaces with concave or convex solid profiles whose area is covered with air cushion pads
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CN102686917A (en) * 2009-11-06 2012-09-19 A.W.切斯特顿公司 Gland packing yarn

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EP1395767B1 (en) 2007-03-28
CA2450697A1 (en) 2002-12-19
MXPA03011543A (en) 2004-06-15
DE10128346A1 (en) 2003-03-06
DE50209832D1 (en) 2007-05-10
ATE358250T1 (en) 2007-04-15
US20040239046A1 (en) 2004-12-02
EP1395767A1 (en) 2004-03-10

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